Screen Printing Device Optical Axis Calibration
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Solution Overview
Problem
Current screen printing devices with two imaging optical axes face errors in directional positioning and require complex calibration processes, leading to inaccuracies in substrate and mask plate alignment, which complicates high-precision printing and makes it difficult to confirm positioning precision during production.
Innovation Solution
A screen printing device with an imaging unit having two imaging optical axes that includes an optical axis calibration processing unit, a surface correction data creation processing unit, and a precision evaluation unit to detect and correct positional deviations, allowing for accurate substrate and mask plate alignment and easy confirmation of positioning precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single imaging unit with two imaging optical axes is used to image substrate and mask plate, then the imaging unit can be moved by a single travel unit to image both objects, but errors occur in the horizontal direction of the two imaging optical axes leading to incorrect position recognition results
Solution Approach 1:
The patent performs optical axis calibration before the actual imaging operation. Reference marks are imaged to detect relative positions of the imaging optical axes, and this calibration data is stored and applied to correct position recognition results during production, preventing errors before they affect output quality
Solution Approach 2:
The patent implements a feedback mechanism where the detected relative positions of imaging optical axes from calibration marks are fed back into the position recognition system. The recognition processing unit uses this feedback information to correct the horizontal position deviations in the imaging results, ensuring accurate substrate and mask plate positioning
2Speed
If ball screws are used for horizontally moving the imaging unit, then the imaging unit can be moved with controlled precision, but local position error occurs between command position and actual moved position
Solution Approach 1:
The patent replaces reliance on mechanical positioning accuracy with optical measurement and computational correction. Instead of depending on the ball screw mechanism's precision, the system uses imaging of reference marks to detect actual optical axis positions and computationally corrects the positioning errors, substituting mechanical precision requirements with optical measurement capabilities
3Measurement precision
If calibration processing is performed to obtain position reference data, then the coordinate system relationship between substrate and mask plate can be established, but complicated operation and processing are required making it difficult to confirm positioning precision during production continuation
Solution Approach 1:
The patent enables the system to perform self-calibration using reference marks that are automatically detected by the imaging unit. The calibration process is automated and integrated into the normal operation flow, allowing the system to maintain its own positioning accuracy without requiring external intervention or complex manual calibration procedures during production
4Area of stationary object
If the imaging unit is moved to different horizontal positions to image different areas, then complete coverage of substrate and mask plate can be achieved, but position error occurs due to local deviation in ball screw positioning
Solution Approach 1:
The patent performs optical axis calibration at each horizontal position before imaging. Reference marks are imaged at different horizontal locations to detect local variations in optical axis relative positions, and this position-specific calibration data is stored and applied to correct position recognition results for each area, ensuring accuracy across the entire imaging coverage
Solution Approach 2:
The patent applies different calibration corrections for different horizontal positions. Instead of using a single calibration result for the entire area, the system detects and applies position-specific optical axis relative position data for each horizontal location where imaging occurs, accounting for local deviations in the ball screw mechanism
Data Source
AI summary
Prior to a mark imaging process executed for the purpose of detecting a position of recognition marks for positioning the substrate and the mask, an optical axis calibration processing process of detecting a horizontal relative position between imaging optical axes, and a surface correction data creation processing process of detecting a local positional deviation of the imaging optical axes, which is caused by the travel of the imaging unit, are executed. Before starting production, a production pre-start precision evaluation process for evaluating a substrate positioning precision is executed by using a verification substrate and a verification mask, and after starting the production, a production post-start precision evaluation process for evaluating a substrate positioning precision after starting the production is executed by using a commercial production substrate and a commercial production mask.